Blights on the wonder drug

Aspirin's reputation was tarnished, first by NSAIDs/heart
attack and now by pancreatic cancer links;
Mr Bayer's rolling in his grave

By Owen Dyer

For years aspirin has been the drug that just keeps getting better. First it was discovered that low-dose daily aspirin could cut the risk of heart attacks. Then it emerged that aspirin can even reduce the danger of stomach cancer. The little pill seems set for a new lease on life, but now research suggests there may be a few flies in the ointment for those who take aspirin every day.

Two recent studies have reported potential problems with long-term aspirin use. By coincidence, one study followed male doctors while the other recruited female nurses as subjects.

NSAID cocktail
In the five-year Physician's Health Study, published recently in Circulation, 22,071 apparently healthy male physicians aged 40-84 years were randomly assigned to receive either 325mg of aspirin or placebo every other day. Researchers compared health outcomes in the aspirin group. They found that doctors who frequently took non-steroidal anti-inflammatory drugs (NSAIDs) in addition to their regular aspirin use did not enjoy a reduced risk of heart attack as might be expected -- in fact their risk was sharply elevated.

Setting the average risk for heart attack in the overall study population at 1.00, the team found an adjusted risk ratio for heart attack of 2.81 among subjects on low-dose aspirin therapy who took NSAIDs at least 60 days a year. This compared with 1.20 for those in the aspirin group who took NSAIDs 1-59 days a year.

NSAIDs taken without aspirin, conversely, seemed to have a protective cardiovascular effect. Men in the placebo group who took NSAIDs for at least 60 days a year had a relative risk of heart attack of 0.21, compared with 1.14 in the men in the placebo group who took NSAIDs for 1-59 days a year. Unfortunately the study failed to differentiate between various types of NSAIDs.

The results indicate that patients on low-dose aspirin who need anti-inflammatory drugs for arthritis or other pain might consider using the more selective COX-2 inhibitors rather than traditional NSAIDs, observed rheumatology specialist Dr Marc C Hochberg of the University of Maryland.

Pancreatic cancer link
Another potentially alarming aspirin study appeared in the Journal of the National Cancer Institute. An analysis of results from the Nurses' Health Study, which has followed 88,378 women since 1980, suggests that those who regularly took aspirin were more likely to develop pancreatic cancer. Women who reported more than 20 years of regular aspirin use had a risk of pancreatic cancer 58% higher than the average for the group. The danger appeared to grow with higher dosages, and those who reported frequently taking more than 14 aspirin a week ran a risk 86% higher than average.

An editorial accompanying the article said there is no obvious mechanism by which aspirin could lead to pancreatic cancer, despite some epidemiological data that suggest NSAIDs can be linked to acute pancreatitis. But the study's methodology is sound, said the editor, and the findings should be accepted at face value.

For the moment there is little anyone can do about it. Pancreatic cancer is deadly but fortunately rare. Only 161 of the 88,378 women in this study developed the disease over an 18-year period. Until more facts are in, physicians are bound to judge that the cardiovascular benefits of aspirin outweigh any cancer risk.